Selection of Tubing

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Selecting the right tube for the job

All four classes of tubing can be used with the capillary solder system. The choice of tubing will depend on the nature of the work to be performed. SABS 460 Class 1, 2 & 3 all have excellent bending qualities. There are various bending machines on the market and those with inner and outer formers make the best bends. The cheaper hand benders and springs do not perform satisfactorily on the above mentioned class of tubes.

  • SANS 460 Class 0 : Is recommended for all above ground work as its use would provide the maximum cost saving benefit. It is emphasized that Class 0 tubing is hard drawn and any change of direction should be made with capillary fittings. Local annealing of Class 0 in order to produce a bend is not recommended. It is most important to remember that SABS 460 Class 0 (hard drawn tube) should NOT be bent under any circumstances. Class 0 tube is ideally suited for use with capillary fittings, however, compression fittings should be avoided where possible. The use of a 90° or 45° capillary soldered elbow will provide a quick, inexpensive and neat crossover bend.
    When compared with traditional systems, capillary systems can realize an installation time saving of up to 70%.
  • SANS 460 Class 1 : This half hard, thin-walled tube is also meant for above ground use. It is also ideally suited for use with capillary or compression fittings. Care should be taken when bending the Class 1 tube as it has a thin wall. We don’t recommend brazing of SANS 460 Class 1. The SANS 460 Class 1 is ideally suited for the T-joints. Sizes 28mm to 108mm.m.
  • SANS 460 Class 2: A half hard, heavy gauge tube with excellent bending qualities. This class is also used underground under normal conditions i.e. non-aggressive soils. This is the only class that can be bent by using an Internal Bending Spring. Care should be taken when installing tube underground. The tube should be protected against external corrosion using CXP tape. SABS 460 Class 2 - 28mm to 108mm is ideally suited for the drawing of “T” joints.
  • SANS 460 Class 3: This class is a heavy, thick walled, half hard copper tube with excellent bending qualities, designed specifically for marine and underground use where soil movement takes place. Care should be taken when installing tube underground and it should be protected against external corrosion using CXP tape.

Half hard tubes bent by hand should have a radius of at least 6 times the outside diameter of the tube and machine bent tubes should have a radius of not less than 3 times the outside diameter of the tube. Any deviation from the above figures could cause a restriction in the tube producing turbulent flow and the possibility of erosion corrosion. Note: Damaged and worn bending equipment will result in a failure.

Copper tubing, due to the very smooth bore, maintains excellent flow characteristics as there is less chance of furring than with traditional materials. 

Because of copper tube’s excellent internal corrosion resistance, tube bores remain smooth and internal diameters constant, thus eliminating the need to account for bore reduction or roughening when computing friction losses as with steel piping. 

Copper’s light weight facilitates shipment, fabrication and installation. When comparing steel pipe systems, weight reductions of up to 50% are afforded by copper systems. This is significant in terms of hanger requirements and dead loads imposed on supporting structural elements. 

Copper is compatible with all types of piping. It is accepted practice to join copper tubing to galvanized piping provided that the copper is downstream from the galvanized pipe. Certain corrosion problems may be experienced under specific conditions if the copper tube is connected upstream. 

When cutting copper tube with tubing cutters or a hacksaw, care should be taken to produce a square end and to remove the burr produced. This will remove the possibility of turbulent flow which could promote erosion corrosion.